共查询到20条相似文献,搜索用时 31 毫秒
1.
A family of sequences has the Ramsey property if for every positive integerk, there exists a least positive integerf
(k) such that for every 2-coloring of {1,2, ...,f
(k)} there is a monochromatick-term member of . For fixed integersm > 1 and 0 q < m, let q(m) be the collection of those increasing sequences of positive integers {x
1,..., xk} such thatx
i+1 – xi q(modm) for 1 i k – 1. Fort a fixed positive integer, denote byA
t
the collection of those arithmetic progressions having constant differencet. Landman and Long showed that for allm 2 and 1 q < m,
q(m) does not have the Ramsey property, while
q(m)
A
m
does. We extend these results to various finite unions of
q(m)
's andA
t
's. We show that for allm 2,
q=1
m–1
q(m) does not have the Ramsey property. We give necessary and sufficient conditions for collections of the form
q(m)
(
t T
A
t) to have the Ramsey property. We determine when collections of the form a(m1) b(m2) have the Ramsey property. We extend this to the study of arbitrary finite unions of q(m)'s. In all cases considered for which has the Ramsey property, upper bounds are given forf
. 相似文献
2.
Abdelhafed Elkhadiri 《Bulletin of the Brazilian Mathematical Society》2000,31(1):45-71
Let be an open subset of
n
and
be a subalgebra of the algebra of analytic functions on . We suppose that
satisfies some weak conditions of noetherianity such that we can construct a finite stratification for each ideal of
. We also suppose that
satifies global £ojasiewicz's inequalities. We prove the following: Let
andf C
on
flat on ; if for eacha the Taylor's serie off ata, T
a
f, is in the ideal generated byT
a
f
1,...,T
a
f
p
in the ring of formal power series, then there exist
1,...,
p
,C
on
flat on such that
. This result extends the classic Hormander's theorem of division (for a polynomial) or the £ojasiewicz-Malgrange theorem in the local analytic case.Reherches menées dans le cadre du Programme d'Appui à la Recherche Scientifique (PARS MI 33) 相似文献
3.
Elena Prestini 《Monatshefte für Mathematik》1988,105(3):207-216
LetfL
p(
n
),n2, be a radial function and letS
Rf be the spherical partial sums operator. We prove that if
thenS
Rf(x)f(x) a.e. asR. The result is false for
and
\frac{{2n}}{{n + 1}}$$
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.Partially supported by M.P.I. 相似文献
4.
Matthew R. Brown 《Journal of Algebraic Combinatorics》2002,15(2):107-125
If a GQ S of order (s, s) is contained in a GQ S of order (s, s
2) as a subquadrangle, then for each point X of S\S the set of points
of S collinear with X form an ovoid of S. Thas and Payne proved that if S=
(4,q),q even, and
is an elliptic quadric for each XS\S,thenS
(5,q). In this paper we provide a single proof for the q odd and q even cases by establishing a link between the geometry involved and the first cohomology group of a related simplicial complex. 相似文献
5.
Edgar R. Lorch 《Integral Equations and Operator Theory》1981,4(3):422-434
The objects studied are the subalgebras of
which contain co. These are isometrically isomorphic to the algebras C(
) where
is a compactification of a discrete denumerable set N . It is shown: 1) If
is metric then there is a projection of norm 1, P: C(
) C(
) with kernel co defined by PF = f o where is a retraction of
onto
=
– N . 2) If
is metric, then the group of homeomorphisms of
is isomorphic to a complete group of permutations of the natural numbers . 3) The group of homeomorphisms of a compact metric space is the homomorphic image of a complete group of permutations of ("complete" means "no outer automorphisms, trivial center"). 相似文献
6.
Real valued M-estimators
in a statistical model 1 with observations
are replaced by
-valued M-estimators
in a new model with observations
where
are regressors,
is a structural parameter and
a structural function of the new model. Sufficient conditions for the consistency of
are derived, motivated by the sufficiency conditions for the simpler parent estimator
The result is a general method of consistent estimation in a class of nonlinear (pseudolinear) statistical problems. If F
has a natural exponential density ex–b( x ) then our pseudolinear model with u = (g o )–1 reduces to the well known generalized linear model, provided () = db()/d and g is the so-called link function of the generalized linear model. General results are illustrated for special pairs and leading to some classical M-estimators of mathematical statistics, as well as to a new class of generalized -quantile estimators. 相似文献
7.
D. M. Smirnov 《Algebra and Logic》2005,44(2):109-116
Let be the set of all primes,
the field of all algebraic numbers, and Z the set of square-free natural numbers. We consider partially ordered sets of interpretability types such as
, and
, where AD is a variety of -divisible Abelian groups with unique taking of the pth root p(x) for every p ,
is a variety of
-modules over a normal field
, contained in
, and Gn is a variety of n-groupoids defined by a cyclic permutation (12 ...n). We prove that
, and
are distributive lattices, with
and
where
ub and
ubf are lattices (w.r.t. inclusion) of all subsets of the set and of finite subsets of , respectively.Deceased.__________Translated from Algebra i Logika, Vol. 44, No. 2, pp. 198–210, March–April, 2005. 相似文献
8.
Salvatore Vassallo 《Geometriae Dedicata》1992,43(3):321-335
Let be a plane lattice and {v
1, v
2} a Minkowski reduced base of . In this note we prove that if a convex body K has minimal width w(K) |v
2| sin +|v
1|(
), where is the acute angle between v
1 and v
2, then K is a covering set for .This work was partially supported by MURST (40–60%). 相似文献
9.
For 1/2<<1 fixed, letE
(T) denote the error term in the asymptotic formula for
. We obtain some new bounds forE
(T), and an _-result which is the analogue of the strongest _-result in the classical Dirichlet divisor problem. 相似文献
10.
Yuanji Cheng 《Czechoslovak Mathematical Journal》1997,47(4):681-687
In this paper, we consider the existence and nonexistence of positive solutions of degenerate elliptic systems
where –p is the p-Laplace operator, p > 1 and is a C
1,-domain in
. We prove an analogue of [7, 16] for the eigenvalue problem with
and obtain a non-existence result of positive solutions for the general systems. 相似文献
11.
Summary The local limit problem is investigated for sequences (p
n
) of probability densities with stable limit densitiesq
having characteristic exponent (0, 2).It is shown that certain continuity-properties (Hölder-continuity) are necessary and - under appropriate additional conditions-sufficient for
asn. In this sence the speed of convergence is also studied. 相似文献
12.
Roshdi Khalil 《Annali di Matematica Pura ed Applicata》1990,157(1):245-249
Summary In this note we prove that: if T is a contraction in L(lp) that maps elements of disjoint support to elements of disjoint support, then T is an extreme point of the unit ball of L(lp), 1
i) form a p-orthonormal sequence or the nonzero elements of (yi) form a p-orthonormal sequence for which supp (yi)=N. 相似文献
13.
A. Cabot 《Journal of Optimization Theory and Applications》2004,120(2):275-303
Let H be a real Hilbert space and let
be a
function that we wish to minimize. For any potential
and any control function
which tends to zero as t+, we study the asymptotic behavior of the trajectories of the following dissipative system:
The (S) system can be viewed as a classical heavy ball with friction equation (Refs. 1–2) plus the control term (t)U(x(t)). If is convex and (t) tends to zero fast enough, each trajectory of (S) converges weakly to some element of argmin . This is a generalization of the Alvarez theorem (Ref. 1). On the other hand, assuming that is a slow control and that and U are convex, the (S) trajectories tend to minimize U over argmin when t+. This asymptotic selection property generalizes a result due to Attouch and Czarnecki (Ref. 3) in the case where U(x)=|x|2/2. A large part of our results are stated for the following wider class of systems:
where
is a C
1 function. 相似文献
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14.
A. Cossidente J. W. P. Hirschfeld G. Korchmáros F. Torres 《Compositio Mathematica》2000,121(2):163-181
The number N of rational points on an algebraic curve of genus g over a finite field
satisfies the Hasse–Weil bound
. A curve that attains this bound is called maximal. With
and
, it is known that maximalcurves have
. Maximal curves with
have been characterized up to isomorphism. A natural genus to be studied is
and for this genus there are two non-isomorphic maximal curves known when
. Here, a maximal curve with genus g
2 and a non-singular plane model is characterized as a Fermat curve of degree
. 相似文献
15.
16.
Majorants and Extreme Points of Unit Balls in Bernstein Spaces 总被引:1,自引:1,他引:0
The Bernstein space B
p () (1
$$
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0) is the set of functions from L
p(
) having Fourier transforms (in the sense of generalized functions) with supports in the compact segment [- , ]. Every function f
has an analytic continuation onto the complex plane, which is an entire function of exponential type . The spaces B
p ()\, are conjugate Banach spaces. Therefore, the closed unit ball
in B
p () has a rich set of extreme (boundary) points:
coincides with the weakly * closed convex hull of its extreme points. Since, for 1< p< , B
p () is a uniformly convex space, only the balls
and
have nontrivially arranged sets of extreme points. In this paper, in terms of zeros of entire functions, we obtain necessary and sufficient conditions of extremeness for functions from
. 相似文献
17.
L. A. Beklaryan 《Mathematical Notes》2002,71(3-4):305-315
In [1] G. Margulis proved Ghys's conjecture stating the validity of the following analog of the Tits alternative: either the group
of homeomorphisms of the circle possesses a free subgroup with two generators or there is an invariant probabilistic measure on S
1
. In the present paper, we prove the following strengthening of Margulis's statement: an invariant probabilistic measure for a group
exists if and only if the quotient group
does not contain a free subgroup with two generators (here
is some specific subgroup of G defined in a canonical way). We also formulate and prove analogs of the Tits alternative for groups
of homeomorphisms of the line. 相似文献
18.
Michael Klemm 《Geometriae Dedicata》1986,20(3):349-356
By a study of the integral code generated by the rows of the incidence matrix and its extention the following results are obtained: Let d
1,...,d
V(d
1|d
2,d
2|d
3...) be the elementary divisors of the incidence matrix of a symmetric (v,n+, ) design. Then d
v=(n+)n/g.c.d. (n, ). Moreover, if p is a prime such that p|n, p and if x
p denotes the p-part of x, then (d
idv+2–i)
p
=n
p for 2iv. For projective planes it can be shown that d
1=···=d
3n–2=1, hence
and
. The paper also contains some results about elementary divisors of incidence matrices G satisfying the condition G
tG=nI+ J.
Elementarteiler von Inzidenzmatrizen symmetrischer Blockpläne相似文献
19.
Let be a triangle in
and let
be the set of its three medians. We construct interpolants to smooth functions using transfinite (or blending) interpolation on
The interpolants are of type f(1)+g(2)+h(3), where (1,2,3) are the barycentric coordinates with respect to the vertices of . Based on an error representation formula, we prove that the interpolant is the unique best L1-approximant by functions of this type subject the function to be approximated is from a certain convexity cone in C3().Received: 17 December 2003 相似文献
20.
J. J. Blair 《Numerische Mathematik》1972,19(2):99-109
Letu be the solution of the differential equationLu(x)=f(x, u(x)) forx(0,1) (with appropriate boundary conditions), whereL is an elliptic differential operator. Letû be the Galerkin approximation tou with polynomial spline trial functions. We obtain error bounds of the form
, where 0jm andmk2m+q,p=2 orp=,h is the mesh size andq is a non negative integer depending on the splines being used.This research was supported in part by the Office of Naval Research under Contract N00014-69-A0200-1017. 相似文献